Tester



FIG. 1 is a perspective view of an embodiment of a tester according to my design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines depict unclaimed environmental subject matter. 

CLAIM The ornamental design for a tester, as shown and described. 